Forbidden Balor View, also known as The Evil Eye that Stops the World, is a Sacred Gear wielded by Gasper Vladi of the Occult Research Club. After evolving and recieving its Longinus certification, it gained the name Aeon Balor, also known as The Evil-Eyed King Who Dominates the Space and Time.
Forbidden Balor View is a Sacred Gear created by the God from the Bible. It was referenced from the Demon God Balor, the most famous God to have possessed the Evil Eyes. In Volume 16, it was revealed that Gasper's Forbidden Balor View has a portion of the consciousness and power of the original Balor residing in it as a result of a young Valerie Tepes unconsciously making use of the Holy Grail to summon and place him into Gasper.
Forbidden Balor View doesn't have any physical form as it is located within the eyes of its wielder.
Forbidden Balor View grants the user the ability to momentarily stop the time of anything within their line of sight. The duration of the effect depends on the user's mastery over the Sacred Gear as well as the target's power relative to the user. The range of effect may be further increased if the wielder is able to generate more eyes through which they could see, such as Gasper invoking the effect through the eyes of multiple bats.
Whether or not the range or duration is affected by the quality of the user's eyesight is unknown.
After awakening the power of Balor of the Evil Eyes, it evolved into a Longinus and developed the power to generate an immense amount of darkness on a scale that can envelop an entire town and devour anything.  Additionally, it can create a large number of eyes within the darkness to stop time for anything within that location. It is also capable of creating numerous beasts of darkness.
In Volume 16, it was revealed that Balor can swap his consciousness with that of others and alternate their line of sight, allowing others to use his time-stopping power, which is how Issei partially froze Shalba during his Juggernaut Drive rampage
Forbidden Invade Balor the Beast (禁夜と真闇たりし翳の朔獣, Fōbidun Inveido Barōru za Bīsuto): Also known as the Shadow Beast Master of the Forbidden Night and True Darkness, it is considered to be a Balance Breaker yet different from a Balance Breaker and has the potential to become the 14th Longinus. It is later classified as one of the new Longinus. First used in Volume 12, it created an enormous amount of darkness, capable of enveloping an entire town, that devours everything (including the mist created by Georg's Dimension Lost, a High-tier Longinus). When used by Balor, the darkness was able to stop the powers of Marius Tepes and the Holy Grail from functioning. While this large area of darkness is active, Gasper can generate twisted monsters to attack opponents, as well as multiple eyes through which he can use Forbidden Balor View, freezing multiple targets at the same time. He is also capable of high-speed regeneration, regrowing his right arm in an instant after it was torn off by Fenrir.
In this form, Gasper's whole body gets covered by the darkness and takes the form of a five meter tall monster with a Dragon head, arms with claws and wings growing from the back.
Forbidden Invade Balor the Princess (禁夜と真闇の滅殺獣姫, Fōbidun Inveido Barōru za Purinsesu): Also known as Beast Ruin Princess of the Forbidden Night and True Darkness, where Gasper melts into his shadow and fuses with Rias' shadow, causing her to become a human-shaped dark beast with ten wings and a third eye with a deep red pupil, and enveloped in a deep red aura of destruction. This combination technique was inspired by Sairaorg's Balance Breaker and her Crimson Extinct Dragonar. In this form, Rias' power exceeds Satan-class, matching Fenrir at 80%, able to freeze opponents using her third eye; stopping and controlling her attacks, travel through shadows; and adding darkness onto her Power of Destruction, casually destroying an area with a radius of a few hundred meters filled with skyscrapers.
However, this form is still incomplete, having a burden on Rias and Gasper, requiring stamina from them in order to maintain it. In this state, she is resistant to both Issei's Dress Break, regenerating the peeled off darkness; and Pailingual, hearing a mixture of Rias' and Gasper's voices, making it difficult to predict what she'll do.
Rias and Gasper alternate lines when chanting the Forbidden Invade Balor the Princess chant.
- Rias: Darkness, everlasting darkness, respond to this Devil of destruction.
- Gasper: Princess of destruction, symbol of extinction, use this darkness of the Demon God.
- Rias: My evil eye, brother of the evil eyes, gather onto this destruction of mine.
- Gasper: My master, sister of destruction, drape this forbidden night and true darkness around you.
- Both: Give the enemy before you absolute destruction!
- Due to the manifestation of Balor's power of darkness, it further strengthened the abilities of Forbidden Balor View, Azazel stated that it has the potential to become the 14th Longinus. In True Volume 1, it became officially classified as one of the five newly manifested Longinus and renamed Aeon Balor.
- Aeon Balor is the first of the 5 newly manifested Longinus to appear in the story, though it wasn't until Volume 25 that Gasper's version of the Sacred Gear was reclassified as a new species of Longinus and renamed into Aeon Balor.
- Aeon Balor is currently the only one of the New Longinus to have its Balance Breaker achieved.
- Forbidden Balor View is a reference to the monstrous Fomorian, Balor of the Evil Eye, whose magical eye had highly dangerous and destructive powers.
- Aeon in various philosophical teaching (such as Neoplatonism, Platonism, and Gnosticism) is a power existing from eternity; an emanation or phase of the supreme deity.
- This reference that a portion of Balor's power was sealed in Gasper's Forbidden Balor View by Valerie Tepes using her Longinus.
- Light Novel Volume 16, Life 3
- Light Novel Volume 25, Life 0
- Light Novel Volume 25, Longinus
- Light Novel Volume 4, Life 3
- Light Novel Volume 4, Life 5
- Light Novel Volume 16, Life 4
- Light Novel Volume 16, Afterword
- Light Novel Volume 12, Life -1
- Light Novel Volume 24, Life 4 The Limits of Humanity and Ultimate Evil Dragon